Gunsmithing Loctite 680 for AR barrel install

[NavyshooterM40]

I am building a .224 Valkyrie with an Aero Precision upper and lower. All other major parts are JP enterprise. I have used Brownells tool to lap the barrel interface on the upper. What is the process for using the Loctite 680 during barrel install?

 

[...]

1. apply loctite
2. insert barrel

 

[NavyshooterM40]

1. apply loctite
2. insert barrel

Should you let it dry before torquing barrel nut?

 

[MarkCO]

Good for picking a product that actually works on passivated metals. However, you also bought an upper made of 7075. There is absolutely no need for a retaining compound unless the barrel extension to upper extension is loose, then you would be better off thermofitting. But I doubt that will be the case. You can safely torque a 7075 upper into the upper end of the "mil specs" and in fact past it to at least 100 ft-lbs without any worry. Most of mine are in the 80 to 100 pound range. It is also what we suggest for our barrels (7075 receivers and 80 to 100 ft-lbs of torque).

 

[Wannashootit]

It doesn't take much, so don't gob it all over the barrel extension. You're only "filling" a few thousandths gap.
Smear some relatively evenly starting at the bottom of the extension, and I leave a "gap" towards the top so any excess will flow there rather than out between the receiver face and extension.

 

[...]

Should you let it dry before torquing barrel nut?

ide torque it all wet, but i seriously doubt youll see a difference either way.

apply it sparingly, rub a thin coat on the barrel extension and the receiver with your fingers.....its designed to fill gaps, and if you have a lapped receiver, its going to be a pretty tight fit, you wont require much (realistically you dont need ANY)......

tighten it all down and let it cure.

 

[whatsupdoc]

Clean both the upper and barrel extension to remove oils with a good solvent.
Apply to loctite to both parts use cotton swab to spread.
Insert barrel into upper wipe off any excess loctite, tighten barrel nut.
Done

 

[Bulletsmith]

Apply moly grease covering threads slightly, Torque barrel nut 3 times. done. dont use locktite.